833 results about "Carbon coating" patented technology

The invention belongs to the technical field of batteries, and discloses a carbon-coated modified lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, and the carbon-coated modified lithium manganese iron phosphate positive electrode material comprises carbon-coated modified lithium manganese iron phosphate positive electrode material particles, the carbon-coated modified lithium manganese iron phosphate positive electrode material particle comprises a lithium manganese iron phosphate core, a first carbon coating layer and a second carbon coating layer, wherein the first carbon coating layer is positioned between the lithium manganese iron phosphate and the second carbon coating layer; the graphitization degree of the first carbon coating layer is greater than that of the second carbon coating layer. The carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high conductivity, compaction density and the like, and a battery using the carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high charge-discharge rate, excellent energy density, excellent capacity and the like.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of a graded ordered silicon-carbon negative electrode material for a lithium ion battery, which comprises the following steps: (S1) mixing phenolic resin and a template agent, calcining, and etching to obtain porous carbon containing macropores; (S2) carrying out cracking and carbon coating on the silicon source gas to obtain nano crystalline silicon containing a carbon coating layer; (S3) mixing the porous carbon with the nano crystalline silicon containing the carbon coating layer, and then carrying out ultrasonic vibration, so that macropores of the porous carbon are filled with the nano crystalline silicon to obtain a silicon-carbon composite material I; (S4) treating the silicon-carbon composite material I by using a carbon-containing sealing agent, and then activating to obtain a silicon-carbon composite material II; and (S5) carrying out vapor phase silicon deposition on the silicon-carbon composite material II to fill the amorphous silicon in the pores of the porous carbon, and then carrying out carbon coating to obtain the graded ordered silicon-carbon negative electrode material. The silicon-carbon negative electrode material prepared by the invention is of a composite structure in which crystalline silicon and amorphous silicon are spatially and orderly distributed, so that the structural stability and the uniform distribution of silicon are realized.

The application specifically discloses a phosphate-based positive electrode material and a preparation method and application thereof. The phosphate-based positive electrode material comprises base particles and a carbon coating layer coated on the surface of the base particles; the chemical formula of the base particles is Li x M y PO4, 0.96≤x≤1.08, 0.96≤y≤1, M comprises at least one of Fe and Mn; wherein, the M site is doped with a first metal element, the first metal element comprises at least one of Ti, V, Cr, Co, Ni, Nb, Mo and W; and / or, the Li site is doped with a second metal element, the second metal element comprises at least one of Mg and Zr; the carbon coating layer comprises a carbon material, and the degree of disorder I D / I G of the carbon material is ≤1.2. The application has the advantages of improving the electrochemical performance of the phosphate-based positive electrode material and reducing the ion elution rate thereof.

The invention belongs to the technical field of material recovery, and particularly discloses a regeneration method of a waste lithium iron phosphate battery positive electrode material, a lithium ion battery positive plate prepared from regenerated lithium iron phosphate powder and a lithium ion battery. Waste lithium iron phosphate powder is uniformly mixed with uric acid and a lithium source, and the mixture is subjected to annealing and annealing treatment in an inert atmosphere, so that structure repair and performance upgrading of a failure material are realized. Uric acid serves as a reducing agent and a carbon-nitrogen source at the same time in the process, Fe < 3 + > is effectively reduced through thermal decomposition of the uric acid, anti-position defects are reduced, a uniform nitrogen-doped carbon coating layer is synchronously formed on the surfaces of particles, and the conductivity and the ion diffusion rate of the material are remarkably improved. The method is short in process flow and environment-friendly, and does not need to use strong acid and strong alkali. The regenerated lithium iron phosphate material has excellent electrochemical performance, the capacity retention rate reaches 91.22% after 500 times of circulation under the multiplying power of 0.5 C, the capacity retention rate is far superior to that of a commercial material, and an effective way is provided for high-valued recovery of waste lithium iron phosphate.

The invention discloses a porous silicon-carbon composite negative electrode material, a one-step preparation method, a lithium ion battery and application, and belongs to the technical field of lithium ion battery materials, the method comprises the following steps: mixing a silicon source, magnesium powder, a carbon source and a soluble pore forming agent to obtain mixed powder; performing high-energy mechanical ball milling on the mixed powder in an inert atmosphere, and performing acid pickling, high-temperature carbonization treatment, cooling, water washing, suction filtration and drying to obtain the porous silicon-carbon composite negative electrode material; the porous silicon-carbon composite negative electrode material comprises a porous shell formed by amorphous porous carbon and a porous core formed by silicon nanoparticles embedded in the porous shell, the mechanical collision energy generated in the high-energy mechanical ball milling process triggers the low-temperature magnesiothermic reduction reaction between the silicon source and the magnesium powder, the carbon source is attached to the surfaces of silicon particles while the silicon particles are generated, and silicon synthesis, carbon coating and pore forming are synchronously achieved. The silicon-based negative electrode has the advantages of high initial coulombic efficiency, high specific capacity, excellent cycle stability and rate capability, and effectively solves the problems of volume expansion and large-scale preparation of the silicon-based negative electrode.

The application provides a negative electrode material and a preparation method thereof and a secondary battery, and relates to the technical field of battery materials. The negative electrode material comprises a silicon-based inner core and a carbon layer coated on the surface of the silicon-based inner core, wherein the silicon-based inner core comprises nanosilicon and a silicate containing a metal element M; the negative electrode material is subjected to section analysis and energy spectrum analysis, and meets the conditions of k1<=10, k2<=5 and 0.1 The preparation method of the negative electrode material comprises the following steps: heating and evaporating pre-disproportionated silicon monoxide material and M metal source material to obtain silicon monoxide gas and metal source gas; mixing and condensing the two kinds of gas to obtain an inner core material; and performing carbon coating treatment to obtain the negative electrode material. In the negative electrode material prepared by the application, the metal silicate effectively separates the nanosilicon domain and the silicon oxide domain, and is uniformly distributed, and the negative electrode material has high initial efficiency and excellent cycle performance.

The invention discloses a lithium supplement agent which comprises a lithium supplement inner core and a carbon coating layer coating the surface of the lithium supplement inner core, and the lithium supplement inner core is doped with an Al element; the lithium supplementing agent meets the condition that A / I is larger than or equal to 0.3 and smaller than or equal to 4, A is the mass ratio of the Al element in the lithium supplementing agent, and I is the ID / IG value of the lithium supplementing agent in a Raman spectrogram. By regulating and controlling the A / I ratio of the Al doping amount to the carbon coating layer structure, the lithium supplementing capacity, the conductivity and the air stability are improved, and meanwhile, the gas production phenomenon in the lithium removal process is effectively inhibited.

The present invention relates to a preparation method for a silicon-carbon composite negative electrode material, comprising the following steps: (P1) co-polymerization: co-dissolving an unsaturated organic acid, an acrylate monomer and an acrylamide monomer in water at a specific ratio, and co-polymerizing same under the action of a sacrificial agent of a saturated organic acid and an initiator to obtain a suspension containing an acrylic copolymer; (P2) alkali treatment: performing an alkali treatment and filtration on the suspension to obtain copolymer particles; (P3) in-situ polymerization: performing in-situ polymerization of phenolic aldehyde on the surfaces of the copolymer particles to obtain a composite resin of a phenolic aldehyde-coated acrylic copolymer; (P4) heat treatment: performing a heat treatment on the composite resin in an oxidizing gas atmosphere to obtain porous carbon; and (P5) performing silicon deposition and carbon coating on the porous carbon to obtain the silicon-carbon composite negative electrode material. When the silicon-carbon composite negative electrode material prepared in the present invention is used in a lithium battery, the volume expansion of silicon can be effectively relieved, and the cycling performance and charge-discharge capacity of a lithium-ion battery are improved.

The invention belongs to the technical field of carbon-coated lithium ferrous silicate, and discloses a preparation method and application of carbon-coated lithium ferrous silicate, the preparation method of carbon-coated lithium ferrous silicate comprises the following steps: S1, adding a surfactant into a silicon source to obtain a solution A; s2, sequentially adding an iron source and a lithium source into the solution A, and uniformly mixing to obtain a carbon-coated lithium ferrous silicate precursor; s3, carrying out high-temperature sintering on the carbon-coated lithium ferrous silicate precursor to obtain carbon-coated lithium ferrous silicate; the surfactant in the step S1 is a block type polyurethane surfactant, and a hydrophilic part structure in the block type polyurethane surfactant comprises polyethylene glycol PEG and 2, 2-dimethylolbutyric acid DMBA. According to the preparation method of the carbon-coated lithium ferrous silicate, the block type polyurethane surfactant is adopted in the step S1 and is not only used as a surfactant, but also used as a reducing agent and a carbon source, and a carbon coating layer of the prepared carbon-coated lithium ferrous silicate is uniform in thickness and excellent in electrochemical performance.

The invention discloses a carbon-coated sodium ferric sulfate positive electrode material, a preparation method thereof and a battery, and the preparation method comprises the following steps: dissolving anhydrous sodium sulfate and ferrous sulfate heptahydrate in a solvent according to a preset proportion, and adding a preset amount of inorganic carbon dispersion liquid to form a uniform suspension; carrying out spray drying on the turbid liquid to obtain a primary coating precursor; dispersing a conductive carbon black material in the solution to obtain a carbon dispersion liquid; putting the primary coated precursor into an aerial fog coating machine, pumping a carbon dispersion liquid into a nozzle, and coating through two-phase flow injection and collision with primary coated precursor powder to obtain a secondary coated precursor; and sequentially calcining, grinding and screening the precursor to obtain the carbon-coated sodium ferric sulfate positive electrode material. The preparation method disclosed by the invention adopts two common industrial treatment modes of spray drying and fluidization coating for preparation, and has the characteristic of easiness in amplification. The fluidization coating can effectively improve the coating uniformity of the solid-phase inorganic carbon on the particle surface.

The invention discloses a composite lithium supplement additive and a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The composite lithium supplement additive provided by the invention comprises a lithium-rich lithium ferrite core; the conductive carbon coating layer and the pentafluoropropionamide coating layer are sequentially coated outside the lithium-rich lithium ferrite inner core from inside to outside, so as to form a core-shell structure. The composite lithium supplement additive prepared by the invention forms a three-dimensional interpenetrating electron transport network, significantly improves the material conductivity, optimizes the charge transfer dynamics, can effectively isolate lithium-rich lithium ferrite from contacting H2O and CO2 in the air, significantly reduces the generation of surface residual alkali, can adapt to the volume expansion of lithium-rich lithium ferrite in the charge-discharge process, and improves the lithium supplement efficiency. And material structure damage caused by interface stress is reduced, so that the cycling stability of the lithium ion battery is greatly improved, the service life of the lithium ion battery is greatly prolonged, and the material has a wide application prospect in the lithium ion battery.

The invention discloses a long-life lithium manganese iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery positive electrode materials. The long-life lithium manganese iron phosphate positive electrode material comprises lithium manganese iron phosphate, a middle coating layer and a carbon coating layer, the surface of the lithium manganese iron phosphate is coated with the middle coating layer, the surface of the middle coating layer is coated with the carbon coating layer, the middle coating layer contains metal fluoride and aluminum-containing sinter, and the aluminum-containing sinter comprises aluminum oxide and lithium metaaluminate. The synergistic coating of the middle coating layer and the carbon coating layer can effectively reduce the contact between the positive electrode material and an electrolyte, inhibit the generation of surface side reactions, improve the stability of the electrode material structure, and have low manganese dissolution and excellent cycle life.

The invention discloses a positive electrode active material, a secondary battery and a power utilization device, and belongs to the technical field of batteries, the positive electrode active material comprises a first lithium-containing phosphate, a carbon coating layer and a lithium manganese iron phosphate coating layer which are sequentially arranged, and S (100) / S (002) is more than 1 and less than 4.5 by controlling S (100) / S (002) to be more than 1 and less than 4.5; the carbon coating layer enhances the bonding effect between the lithium-containing phosphate and the lithium-manganese-iron phosphate, is beneficial to charge transfer, improves the structural stability of the whole material and promotes the intercalation and deintercalation of lithium ions, and the first lithium-containing phosphate can effectively promote the intercalation of active lithium and effectively improve the gram volume of the lithium-manganese-iron phosphate, so that the service life of the lithium-manganese-iron phosphate is prolonged. The lithium death phenomenon in the charging and discharging process is effectively improved, the cycle life and the rate capability of the secondary battery are effectively improved, and the gas production phenomenon of the secondary battery is improved.

The invention relates to a diamond-like carbon coating and a preparation method thereof, and belongs to the technical field of coatings. The preparation is carried out in a closed field unbalanced magnetron sputtering system, and the system is at least provided with a titanium target, a graphite target and a linear ion source; the preparation method comprises the following steps: pretreating a base material, removing surface moisture, transferring the base material into a vacuum chamber, and carrying out ion cleaning and activation; adjusting bias voltage, then turning on a titanium target power supply, cleaning a target surface, depositing a gradient layer, turning off the titanium target power supply, turning on a graphite target power supply to carry out hydrogen-free deposition, and after deposition is finished, carrying out furnace cooling in a vacuum environment. According to the diamond-like carbon coating provided by the invention, the graphite target material is adopted, under the condition that hydrogen-containing gas and a metal transition layer are not introduced, a closed field unbalanced magnetron sputtering technology is combined with linear ion source auxiliary deposition, the DLC coating with excellent biocompatibility is prepared, and the problem of biotoxicity caused by element dissolution is greatly reduced.

The invention discloses a double-carbon-layer-coated spherical silicon carbon material which is characterized in that spherical silicon carbon is used as an inner core, the outer surface of the spherical silicon carbon is sequentially coated with an isotropic hard carbon layer and a composite carbon layer, and the isotropic hard carbon layer and the composite carbon layer form a double-layer carbon coating layer; the spherical silicon carbon is a composite porous carbon microsphere in which disordered silicon is uniformly distributed and the surface is provided with a silicon-oxygen layer; the composite porous carbon microspheres comprise isotropic soft carbon and isotropic hard carbon, and the composite carbon layer comprises graphitized carbon and isotropic soft carbon; the mass of the isotropic soft carbon and the isotropic hard carbon in the composite porous carbon microspheres accounts for 42%-76% of the mass of the double-carbon-layer-coated spherical silicon carbon material, and the mass of the disordered silicon accounts for 22%-76% of the mass of the double-carbon-layer-coated spherical silicon carbon material; the oxygen element accounts for 0.1-2% of the mass of the double-carbon-layer-coated spherical silicon carbon material; the nitrogen element accounts for 0-0.08% of the mass of the double-carbon-layer-coated spherical silicon carbon material; the comprehensive performance of the silicon-carbon negative electrode material, the rate capability of the battery and the capacity reversibility are improved.

The invention discloses a tellurium-doped copper sulfide-based nano composite material with a core-shell structure as well as a preparation method and application thereof, and belongs to the technical field of zinc ion battery negative electrode materials. The method comprises the following steps: dissolving a copper source, a sulfur source, a carbon source and a tellurium source in a mixed solution of deionized water and ethylene glycol, uniformly stirring and mixing, carrying out hydrothermal reaction and centrifugal cleaning, collecting a precipitation product, and carrying out vacuum drying; and carrying out calcination reaction to obtain the tellurium-doped copper sulfide-based nano composite material with the core-shell structure. The inner-layer microspheres are microspheres formed by stacking tellurium-doped copper sulfide flower-shaped nanosheets; and the outer coating layer is a carbon layer. Through the synergistic effect of tellurium doping and carbon coating, the electron conduction and the structural stability of the material are effectively enhanced, and the cycle performance and the rate capability of the aqueous zinc ion battery are remarkably improved. As a negative electrode of the zinc ion battery, the material can effectively improve cyclic reversibility, has remarkable reversible capacity, improves the performance of the zinc ion battery, and is suitable for industrial production and large-scale energy storage.

The invention discloses a silicon-carbon composite material and a preparation method thereof, and belongs to the field of lithium batteries. The preparation method specifically comprises the following process steps: pre-carbonization of a biomass material, gas activation and pickling purification, nano silicon vapor deposition and primary vapor carbon coating, mixed sintering with an elastomer filling material, and secondary vapor carbon coating. A large number of mesoporous channels exist in the obtained silicon-carbon composite material, nanometer silicon crystal particles are deposited in the channels, the surfaces of the particles are coated with a primary carbon coating layer, nanometer silicon can be effectively prevented from being oxidized, then an elastomer filling material is molten in the sintering process to enter reserved spaces of the channels, remaining gaps are filled, and the mechanical property of the composite material is improved. According to the preparation method, the volume expansion effect of nanometer silicon in the lithiation process can be effectively buffered, the mechanical strength can be enhanced, finally, through secondary gas-phase carbon coating, a continuous carbon layer is formed on particles, volume expansion can be relieved, and the electronic conductivity and the cycling stability of the material can be improved.

The invention discloses a battery monomer, a battery device, a power utilization device and an energy storage device. The battery monomer comprises a laminated battery cell, the laminated battery cell comprises a positive pole piece, the positive pole piece comprises a positive pole film layer, and the positive pole film layer comprises lithium-containing transition metal phosphate of which at least part of the surface is provided with a carbon coating material; the thickness H of the single side of the positive electrode film layer is 70 microns to 120 microns; on the basis of the total area of particles in a tangent plane in the thickness direction of the pole piece in a first area, close to the bottom of a positive electrode current collector, of a positive electrode film layer, the area proportion of first particles with the particle size R1 being larger than or equal to 1000 nm is 12%-50%, and in a spheroidic area cumulative distribution curve of the first particles in the tangent plane in the thickness direction of the pole piece in the first area, the median LR1A150 of the sphericity-like degree ranges from 0.6 to 0.8; and when the single battery is in a full discharge state, the compaction density of the positive pole piece is 2.3 g / cm < 3 >-2.6 g / cm < 3 >.

The invention relates to the technical field of batteries, and discloses a negative electrode active material and a preparation method thereof, a sodium ion battery and an electric device. The negative electrode active material comprises a hard carbon material; the hard carbon material comprises a porous hard carbon core and a hard carbon coating layer; the hard carbon coating layer is coated on the surface of the porous hard carbon core; the holes of the hard carbon material comprise closed holes; the specific surface area of the hard carbon material is 1-10m < 2 > / g. According to the application, the hard carbon coating layer is coated on the surface of the porous hard carbon material, open pores of the porous hard carbon are transformed into a closed pore structure, and the closed pore structure is beneficial to sodium ion storage and also enables an electrolyte not to enter and be decomposed easily. The specific surface area of the hard carbon material is within the range of 1-10m < 2 > / g, and the hard carbon material is suitable for the sodium ion battery.

The present application belongs to the technical field of secondary batteries, and specifically relates to a lithium iron phosphate composite cathode active material, and further discloses a preparation method thereof, as well as an application thereof for use in the preparation of battery plates and secondary batteries. The lithium iron phosphate composite cathode active material of the present application comprises a core containing a lithium iron phosphate material and iron phosphide particles, as well as a carbon coating layer and / or a LiBO2-containing coating layer at least partially coated on the surface of the core.

The invention relates to the technical field of graphite negative electrode materials for lithium ion batteries, a surface coating layer structure of the graphite negative electrode material is finely designed to obtain a fast-charging graphite negative electrode material, the fast-charging graphite negative electrode material is provided with a core-shell structure, the core-shell structure takes graphite particles as an inner core, and the surface of the inner core is provided with a carbon coating layer with an ultra-micro pore structure; the pore opening diameter of the ultra-micro pore structure is 0.3-2.0 nm, the pore cavity diameter of the ultra-micro pore structure is 0.5-3.0 nm, and the pore opening diameter of the pore opening is smaller than the pore cavity diameter. A coating layer with an ultra-micro pore structure is introduced to the surface of the graphite negative electrode material, and the structural characteristics of pore cavities and pore openings in the ultra-micro pore structure are finely designed, so that the desolvation speed of lithium ions in an electrolyte on the surface of the material is increased, and the interface structure stability of the graphite negative electrode material can be effectively improved in the process; therefore, the fast charging performance and the cycle performance of the graphite negative electrode material can be effectively improved.

The invention relates to the technical field of preparation of positive electrode materials, and discloses a method for preparing a lithium iron phosphate positive electrode material from an atom-doped carbon coating layer, in particular to a method for preparing a lithium iron phosphate positive electrode material from the carbon coating layer on the surface of the lithium iron phosphate positive electrode material containing a plurality of heteroatoms M, and the molecular formula of the heteroatoms M is LiFePO4 / C (at) M. The preparation method comprises the steps of grinding twice and sintering, the structure of the carbon material is adjusted by utilizing the synergistic coupling characteristic of doped atoms, and the high electron mobility and ion mobility of the lithium iron phosphate positive electrode material are enhanced. The prepared positive electrode material has excellent electrochemical performance, and the charge-discharge specific capacity and the rate capability are improved.

The invention provides a three-dimensional silicon negative electrode material and a preparation method and application thereof. The three-dimensional silicon negative electrode material comprises a porous silicon material, and the pore wall surface and the particle outer surface of the porous silicon material are coated with an oxide layer, a carbon coating layer and a solid electrolyte layer; and the outer surfaces of the particles of the porous silicon material are coated with conductive polymer layers. According to the three-dimensional silicon negative electrode material, the hole wall surfaces and the outer surfaces of the particles are coated with the oxide layers, the carbon layers and the solid electrolyte layers, so that the structural stability of the material is guaranteed, an electron transmission channel and an ion transmission channel are further constructed, and meanwhile, the outer surfaces of the particles are further coated with the conductive polymer layers; and the structural integrity of the three-dimensional silicon negative electrode material in the circulation process is ensured.

The invention discloses a battery and a power utilization device, the battery comprises a positive plate and an electrolyte, the positive plate comprises a positive electrode material, the positive electrode material comprises a positive electrode active material, the positive electrode active material comprises lithium iron phosphate and an iron-containing lithium supplement agent, the lithium iron phosphate comprises an inner core and a carbon coating layer, the thickness of the carbon coating layer is b nm, and the thickness of the carbon coating layer is b nm. The ratio of the Fe < 3 + > peak area to the O1s peak area in the XPS map under the 210nm etching depth in the positive plate is a, the viscosity of the electrolyte under the condition of 25 DEG C is c mPa.s, and a, b and c meet the condition that a * c * b is more than or equal to 1.5 and less than or equal to 40. The invention can give consideration to both fast charging and long service life of the battery.

The invention belongs to the technical field of batteries, and particularly relates to a positive active material, a preparation method thereof and a battery. Compared with the prior art, the method has the advantages that the content of the lithium-containing lithium supplement agent and poor conductivity of the positive electrode active material caused by addition of the lithium-containing lithium supplement agent are indirectly reflected through the difference value between the ratio of Li / Fe in the positive electrode active material and the ratio of Li / Fe in the inner core, so that the conductivity of the positive electrode active material is improved by controlling the relationship between the difference value and the thickness / particle diameter of the first carbon coating layer; the conductivity of the positive electrode active material is improved, and the fast charging performance and cycle performance of the battery are improved.

The invention relates to a carbon-coated lithium iron phosphate material and a preparation method thereof, a positive plate and a battery. The carbon-coated lithium iron phosphate material comprises a lithium iron phosphate matrix and a carbon coating layer at least partially coating the lithium iron phosphate matrix, and the carbon coating layer comprises a carbon material doped with a silicon element and a boron element. According to the carbon-coated lithium iron phosphate material, the surface of the lithium iron phosphate matrix is coated with the carbon coating layer, and the carbon material in the carbon coating layer is doped with the silicon element and the boron element, so that the electronic conductivity of the lithium iron phosphate material can be improved; in addition, doping sources of the silicon element and the boron element can react with magnetic substances such as iron phosphide in the coating process to be converted into non-magnetic inert substances, then the content of magnetic foreign matter impurities in the carbon-coated lithium iron phosphate material is reduced, the overcharge problem is solved, the carbon-coated lithium iron phosphate material has good overcharge prevention performance, and the safety performance is improved.

The invention discloses a high-entropy ferric pyrophosphate sodium ion battery positive electrode material and a preparation method thereof, and belongs to the field of battery positive electrode materials. The chemical formula of the positive electrode material is Na4Fe3-aMa (PO4) 2P2O7 (0.05 < = a < = 0.5), M is a metal element and comprises at least five of cobalt, magnesium, zirconium, zinc, aluminum, molybdenum, copper, manganese, nickel, calcium and chromium, the high-entropy ferric sodium phosphate pyrophosphate battery positive electrode material is spherical, and the surface of the high-entropy ferric sodium phosphate pyrophosphate battery positive electrode material is coated with an amorphous carbon layer. The preparation method adopts a sol-gel method and comprises the following steps: mixing an iron source, a doped metal source, sodium pyrophosphate, ammonium dihydrogen phosphate and citric acid monohydrate according to a stoichiometric ratio, stirring, gelatinizing and drying to obtain xerogel, and calcining through a two-stage hydrogen-argon mixed gas to obtain the iron-doped metal-doped sodium pyrophosphate / citric acid composite material. The crystal structure is optimized by means of the high-entropy synergistic effect, the electron conductivity and the Na < + > diffusion rate are improved, and the industrial adaptability of the spherical morphology and the structural stability of carbon coating are combined.

The invention provides a ferric sodium pyrophosphate positive electrode material, a preparation method thereof and a sodium ion battery. The ferric sodium phosphate pyrophosphate positive electrode material comprises a ferric sodium phosphate pyrophosphate / carbon composite material core and a carbon coating layer, the chemical formula of the sodium ferric pyrophosphate / carbon composite material core is Na (4-x) AxFeyB (2.91-y) (PO4) 2-z / 3P2O7Fz / C, x is greater than or equal to 0.01 and less than or equal to 1, y is greater than or equal to 2.7 and less than 2.91, z is greater than or equal to 1 and less than or equal to 3, A comprises any one or a combination of at least two of Li, K or Ca, and B comprises any one or a combination of at least two of Mg, Al, Zn, V, Co, Mn, Zr, Ti, Cu or Y. According to the invention, the conductivity, rate capability, cycle life and stability of the sodium ferric phosphate pyrophosphate positive electrode material are comprehensively improved through the bulk phase composite carbon and surface carbon-coated dual carbon structure in combination with regulation and control of the sodium ferric phosphate pyrophosphate component.

The invention relates to the technical field of battery silicon negative electrodes, in particular to a silicon-carbon composite material and a preparation method and application thereof. The silicon-carbon composite material comprises a three-dimensional through mesoporous carbon skeleton, nano silicon particles loaded in mesopores and a gradient carbon coating layer, nano silicon and the carbon skeleton are connected through Si-O-C covalent bonds, and the gradient carbon coating layer is composed of a soft carbon inner layer, a graphitized carbon middle layer and a compact hard carbon outer layer. The preparation method comprises three steps of synthesis of a three-dimensional through mesoporous carbon skeleton, confinement silicon loading and gradient carbon coating. The material solves the problems of silicon particle agglomeration, volume effect and interface instability, has excellent electrochemical performance, can be used as a lithium ion battery negative electrode material, is suitable for a next-generation high-energy lithium ion battery, and improves the cycling stability and capacity performance of the battery.

The invention relates to the technical field of lithium ion battery manufacturing, and discloses a preparation method of a silicon-containing silicon oxide-phenolic resin-artificial graphite composite negative electrode material, which comprises the following steps: grafting phytic acid on the surface of silicon-containing silicon oxide to construct a protonated acidic site, mixing modified silicon-containing silicon oxide, phenolic resin and artificial graphite, and keeping at a constant temperature to obtain the silicon-containing silicon oxide-phenolic resin-artificial graphite composite negative electrode material. Preferentially carrying out pre-polycondensation by utilizing phytic acid catalysis interface resin to form a gel layer, and rapidly removing a solvent to obtain a precursor; according to the preparation method disclosed by the invention, interface chemical anchoring is established before solvent volatilization by utilizing a dynamic competitive mechanism, so that the problem of stripping of resin and active particles caused by solvent volatilization in a traditional process is solved, and the structural stability and the electric conduction continuity of the material in a battery circulation process are improved.